1. Field of the Invention
The present invention relates to a translation machine which is capable of generating a natural translated sentence. More particularly, the invention relates to the translation machine which is capable of translating an input sentence in accordance with a sentence pattern of the input sentence by an interaction with an operator.
2. Description of the Related Art
The inventors of the present invention know that there have been traditionally proposed some translation machines. A known translation machine mainly includes a CPU, a translation module, and storage units for storing a main dictionary, a user dictionary, grammatical rules and tree-structure converting rules. In operation, the above-mentioned translation machine is adapted to input a sentence described in a source language from a keyboard into a translation module under the control of the CPU and to translate the sentence described in the source language into a sentence described in a target language in the translation module using the main and user dictionaries and the grammatical and tree-structure converting rules.
In executing the translation from English to Japanese, for example, the above-mentioned translation module serves to divide the input sentence described in English word by word and to obtain grammatical information such as a Japanese equivalent to each word or a part of speech of the Japanese equivalent by consulting the dictionaries stored in the storage unit. If the subject word has two or more parts of speech, the Japanese equivalent matching to each part of speech can be output. As such, in translating the English sentence into a Japanese equivalent, the above-mentioned translation module generates two or more Japanese equivalent candidates on a basis of the part of speech obtained by consulting the dictionaries. It results in that the English sentence is ambiguously interpreted.
For example, when the English sentence "Time flies like an arrow" is input, some Japanese equivalents are provided depending on the interpretation of the part of speech of each word. That is, "Time" may be interpreted as a noun or a verb, "flies" may be interpreted as a noun or a verb, "like" may be interpreted as a noun or a preposition. The resulting Japanese equivalents are as follows:
1. " "(ya-no-youna-jikan-bae) (meaning that "arrow-analogous flies (insects) called as time")
2. " "(ya-no-youni-hae-wo-hakare) (meaning that "Measure flies as if an arrow moves through air")
3. " "(ya-no-youna-hae-wo-hakare) (meaning that "Measure arrow-analogous flies")
4. " "(jikan-bae-wa-ya-wo-konomu) (meaning that "Flies called as time are fond of an arrow")
5. " "(jikan-wa-ya-noyouni-tobu) (meaning that "Time passes as if an arrow moves through air")
A selection of a proper Japanese equivalent from these Japanese equivalent candidates depends on an operator's judgment.
For automating this part of translation, the above-mentioned translation machine works as follows. When an English sentence is input, the above-mentioned translation module takes the steps of dividing the English sentence into words by consulting the dictionaries for each word, and storing the combination of each speech part of each English word and its Japanese equivalent in a dictionary-consulting buffer. If the English word has two or more parts of speech, two or more combinations of each part of the English word and each Japanese equivalent are stored in the dictionary-consulting buffer. Then, the next process is to read the combinations for each word out of the dictionary-consulting buffer in accordance with the predetermined rules and to generate the Japanese equivalents on a basis of the combinations. One example of those Japanese equivalents is such that;
______________________________________ Input English Time flies like an arrow. Sentence: Part of Speech: Noun Noun Preposition Noun Japanese equivalent " " candidate: (ya-no-youna-jikan-bae) (meaning that "Arrow-analogous flies (insect) called as time") ______________________________________
If the candidate is not proper, the operator instructs the CPU to accept or correct the part of speech for each word, thereby the accepted or the corrected part of speech is fixed. The above-mentioned translation module serves to read the part of speech for another word and to reorganize the combination of parts of speech of each word composing the English sentence by reading another part of speech for another word from the dictionary-consulting buffer. The translating process of the reorganized combination results in offering the next combination of the parts of speech of the English sentence and its Japanese equivalent candidate. The above mentioned translation module produces the operation by the interaction with the operator. The above-mentioned repeated operations result in offering a high-quality translated sentence.
However, the above-mentioned translation machine cannot grasp which word is ambiguous considering a result of an interpretation, thereby it reads one combination of a speech part of each word composing the input sentence described in English and its Japanese equivalent depending on the predetermined rules stored in the dictionary-consulting buffer, and translates based on the combination and generates the translated equivalent candidate. Then, the operator accepts or corrects the part of speech of each English word by watching the translated equivalent candidate on the CRT. it results in removing ambiguity of the input sentence in an interactive manner with the operator.
The above-mentioned translation machine is designed to remove interpretative ambiguity of an input sentence by the operator's trial and error, thereby it requires the operator to keep an interaction with the machine, and as a result, the overall process of the translation is inefficient.
Further, the above-mentioned translation machine is designed to define the syntax structure of the input sentence on a basis of the grammatical rules stored in the memory. It results in that the translation machine outputs two or more translated equivalents when the verb contained in the input sentence has two or more sentence patterns. Hence, a user has to do the annoying operation of selecting a proper translated equivalent from the output translated equivalents.
In the following part, a process of finding a title of each English (source language) word for consulting the dictionaries used for the above-mentioned translation machine will be described in detail. Normally, in the dictionaries, the title of the English word is registered in lowercase. However, the word placed at the head of the input sentence has an uppercase at the head. Hence, the word placed at the head of the input sentence may be determined not to be registered in the dictionaries. For avoiding it, before consulting the dictionaries for the sentence-head word, the uppercase placed at the head of the word is converted into the lowercase. This dictionary-consulting mode is referred to as a standard mode.
On the other hand, for a specific sentence consisting of uppercases only such as a telex description, the standard mode is not effective. Hence, for such a sentence including the uppercases in the sentence-head word as well as the other words, all the uppercases included in the sentence are converted into the lowercases before consulting the dictionaries. This dictionary-consulting mode is referred to as an uppercase mode.
The above-mentioned translation machine requires an operator to select the standard mode or the uppercase mode in accordance with the input sentence.
For setting the dictionary-consulting mode, the above-mentioned translation machine automatically sets it as the standard mode in a case that no mode is set by the operator. When the standard mode is selected by the operator, the translation machine sets it as the standard mode. When the uppercase mode is selected by the operator, the translation machine sets it as the uppercase mode.
However, an ordinary sentence has both lowercases and uppercases. For example, a proper noun often contains an uppercase. At the standard mode, therefore, the translation machine does not convert the uppercases into the lowercases except that placed at the head of the sentence. The word having an uppercase is determined not to be registered in the dictionaries only if the uppercase does not appear at the head of the sentence. As a result, disadvantageously, the translation machine outputs the original English word as its translated equivalent. It means that it is necessary to set the dictionary-consulting mode as the uppercase mode for making effective use of the contents stored in the dictionaries.
If the dictionary-consulting mode is always set to the uppercase mode, the uppercase placed at the head of a proper noun, such as the name of a person, is converted into the lowercase even though it is not desired. In this case, if the dictionaries have a translated equivalent word to the proper noun, it results in disadvantageously outputting an erroneous Japanese equivalent as described below.
Input word: Mr. Brown
Translated equivalent
Standard mode: Brown (Shi: meaning a Japanese equivalent of "Mr.") PA1 Uppercase mode: (Chyairo.shi: "Chyairo" is a Japanese equivalent of a brown color)
Both of the above-mentioned disadvantages in the dictionary-consulting mode result in that the standard mode or uppercase mode is indiscriminately set without considering each word of the input sentence.